build: Remove CMP0011 OLD policy

This policy allowed included files and modules to affect policy in the
parent scope. Besides the top level, 3rdparty/libprojectm is the only
place where old policy is set.

Reference: https://cmake.org/cmake/help/latest/policy/CMP0011.html

CMakeLists.txt

@@ -1,7 +1,6 @@
 project(clementine)
 
 cmake_minimum_required(VERSION 3.0.0)
-cmake_policy(SET CMP0011 OLD)
 cmake_policy(SET CMP0053 OLD)
 
 include(CheckCXXCompilerFlag)

src/CMakeLists.txt

@@ -52,7 +52,6 @@ if(HAVE_SPOTIFY)
   include_directories(${CMAKE_BINARY_DIR}/ext/libclementine-spotifyblob)
 endif(HAVE_SPOTIFY)
 
-cmake_policy(SET CMP0011 NEW)
 include(../cmake/ParseArguments.cmake)
 
 if(HAVE_TRANSLATIONS)